1. Field of The Invention
This invention relates to a dipstick assembly for use with an internal combustion engine to enable the lubricant level in the sump of the engine to be checked.
2. Description of the Prior Art
A conventional dipstick assembly comprises a dipstick formed from strip metal which is located in a tube mounted on and extending from the sump of the engine. The end portion of the dipstick extends into the lubricant and by withdrawing the dipstick from the tube it is possible to assess the lubricant level, the end portion of the dipstick being graduated for this purpose.
The checking of the lubricant level requires a conscious effort on the part of the vehicle operator and even if the vehicle operator checks the lubricant level at regular intervals, a sudden reduction of the level of lubricant may escape the attention of the operator. The reduction in lubricant level may result in damage to the engine. It is known to provide a sensor which can provide in conjunction with external electrical components, a signal when the level of lubricant falls to a dangerous level. Such a sensor is known which is built into the engine structure. This form of sensor is expensive and may require considerable effort to secure it to the engine as an accessory. Another form of sensor is known which replaces the conventional dipstick. This form of sensor requires electrical leads of substantial length to enable the sensor to be withdrawn from the tube in order to assess the lubricant level in the engine sump, in the usual way. The presence of long electrical leads is undesirable. Another version utilizes surface contacts on the handle of the dipstick which co-operate with contacts at the upper end of the tube. This version is prone to contamination of the contacts by dirt.